Dongguk University creates stretchable gel nanogenerators for wearable tech

Dongguk University creates stretchable gel nanogenerators for wearable tech
by Riko Seibo
Tokyo, Japan (SPX) Dec 10, 2024

Imagine a world where wearable devices seamlessly integrate into clothing, powering gadgets and offering secure user interactions. Researchers at Dongguk University have unveiled a gel polymer-based triboelectric nanogenerator (GPE-TENG) capable of converting body movement into electrical energy. This innovation not only powers devices like LEDs but also functions as a self-powered touch panel for biometric recognition, showcasing a significant leap in wearable technology.

The newly developed GPE-TENG is stretchable up to 375% of its original size and remains highly durable, even under intense mechanical stress. This makes it ideal for applications such as smartwatches, fitness trackers, and medical sensors, which require flexibility to adapt to human movement. Triboelectric nanogenerators (TENGs) like this one harness mechanical energy-such as motion or touch-into electricity, providing a sustainable alternative to batteries for wearables.

Addressing Flexibility Challenges in Wearables

Traditional TENGs often rely on rigid triboelectric materials that limit adaptability in wearable designs. To overcome these constraints, Professor Jung Inn Sohn and his team at Dongguk University developed a gel polymer electrode-based solution. The GPE-TENG combines polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) gel with ecoflex layers, creating a device that is both semi-transparent and highly flexible.

"We report an in-situ curing strategy to develop a stretchable, semi-transparent, and durable GPE-TENG through enhanced interfacial bonding between the ionic polymer gel and ecoflex layers," explained Prof. Sohn.

The fabrication process involves pouring the gel mixture into an ecoflex mold, spreading it evenly, and covering it with an additional ecoflex layer. After attaching a copper wire for electrical connections, the device is cured at 70 C for 12 hours to ensure a strong bond between the components.

Unprecedented Durability and Performance

The GPE-TENG generates electrical signals when stretched or tapped, achieving a peak power output of 0.36 W/m under a load of 15 MO. Rigorous testing demonstrated its resilience, withstanding two months of continuous bending, twisting, folding, and stretching without performance degradation or structural delamination.

With its impressive durability and energy-generating capabilities, the GPE-TENG can support diverse applications. For instance, it could serve as a rehabilitation tool to track joint movements or as a secure biometric system integrated into clothing to unlock doors and lockers.

"This work could revolutionize wearable technology by developing sustainable and flexible electronic devices with promising applications in human healthcare, rehabilitation, security systems, and secure biometric authentication systems," said Prof. Sohn.

Research Report:In-situ cured gel polymer/ecoflex hierarchical structure-based stretchable and robust TENG for intelligent touch perception and biometric recognition